Product Introduction
Refrigerant (R134a, R-410a, R-407c) Sensor SP-42A-00 Description:
The SP-42A is a SnO2 semiconductor gas sensor with high sensitivity to HCFS (such as refrigerant R134a) and improved resistance to interference from other gases. This product is suitable for leak detection of refrigerant gases R134a, R-410a, R-407c.
Refrigerant (R134a, R-410a, R-407c) Sensor SP-42A-00 Parameters:
Structure
The gas sensing semiconductor material is attached to an aluminum substrate, with gold electrodes printed on the substrate. A thin ruthenium oxide heater is printed on the back of the substrate and housed in a plastic package (Fig1).
Operating Conditions
Fig2 shows the standard circuit for this product. The change in sensor resistance (Rs) results in a voltage change across the load resistor (RL). For optimal performance and parameters, the values of heater voltage (VH), circuit voltage (Vc), and load resistance (RL) must be within the specified standard operating conditions, as detailed in the parameter table on the next page.
Sensitivity Characteristics
Fig3 shows the sensitivity parameter curves of the SP-42A (typical data). The sensitivity parameters of the gas sensor reflect the relationship between sensor resistance and gas concentration. Based on logarithmic function, as sensor resistance decreases, the measured gas concentration increases. The sensitivity parameters of the SP-42A are detailed by the following parameters.
--Sensor resistance: in air containing 100ppm R-134a
--Sensor resistance change rate: in air containing 100ppm to 300ppm R134a
Specific Parameters
A. Standard Operating Conditions
| Symbol |
Parameter |
Specification |
Condition |
| VH |
Heater Voltage |
5V ±4% |
AC or DC |
| VC |
Circuit Voltage |
5V ±4% |
AC or DC |
| RL |
Load Resistance |
Variable |
PS<15mW |
| RH |
Heater Resistance |
40 Ω ± 2Ω |
Room temperature |
| PH |
Heater Power Consumption |
400mW |
PH = VH2 / RH |
| PS |
Sensor Power Consumption |
Less than 15mW |
PS=(VC - VRL)2/RS |
B. Environmental Conditions
| Symbol |
Parameter |
Specification |
Condition |
| Tao |
Operating Temperature |
-10~60°C |
Recommended range |
| Tas |
Storage Temperature |
-20~70°C |
|
| RH |
Relative Humidity |
<95%RH |
|
| （O2） |
Oxygen Concentration |
21% ± 1% (standard condition) |
PhaseFor lower values: >18% |
| Sensitivity parameters are affected by changes in oxygen concentration. |
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C. Sensitivity Parameters
| Model |
SP-42A-00 |
||
| Symbol |
Parameter |
Specification |
Condition |
| RS |
Sensor Resistance |
4kΩ~40kΩ |
In air with 100ppm R-134a |
| β |
Sensitivity Slope |
0.5~0.65 |
RS in air with 300ppm R-134a / RS in air with 100ppm R-134a |
| R/Rair |
Impedance change in gas / Impedance in air |
≤ 0.40 |
RS in air with 100ppm R-134a / RS in air |
| Standard test conditions: Temperature: 20 °C ± 2 °C, VC: 10.0 V ± 1% |
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D. Mechanical Structure Parameters
| Item |
Condition |
Specification |
| Vibration |
Frequency: 100cpm |
Should meet satisfactory specifications in sensitivity parameters |
| Shock |
Acceleration: 100G |
E. Component Materials
| No. |
Part |
Material |
| 1 |
Sensing Element |
SnO2 |
| 2 |
Substrate |
Al2O3 |
| 3 |
Wire |
Au-Pd-Mo |
| 4 |
Heater |
RuO2 |
| 5 |
Electrode |
Au |
| 6 |
Plastic Housing |
Nylon 46 (UL84HB) |
| 7 |
Plastic Base |
Nylon 66 (UL94HB) |
| 8 |
Stainless Steel Mesh |
SUS316 (100 mesh, double layer) |
| 9 |
Heater/Electrode Pins |
Nickel |
Volume
